It Won't Last
by NozomumPrincessPana
Summary: Whilst there was an unavoidable pit of pure despair that Dia felt form in her gut, another thought came to mind after Mari and Ruby had come to let her know that they were dating. It wouldn't last.


Whilst there was an unavoidable pit of pure despair that Dia felt form in her gut, another thought came to mind after Mari and Ruby had come to let her know that they were dating.

It wouldn't last.

Which is why, in an almost unsettlingly calm move for Dia, she wore an expression as though it was carved into her face, tapping her pen against a groove in the desk and looked up at the both of them, thanking them for their time and ushering them out of the room.

Mari and Ruby, despite having known her for years, weren't quite sure what had happened. There wasn't even a congratulations, nor a beratement, or the expected 'stay away from my sister or I'll kill you' routine. Just… Silence. Even from inside the office. Ruby had at least expected some kind of noise inside, whether it be a desk flipping over or rather loud complaints. Maybe she thought it was a joke, Mari's speciality?

Mari and Ruby exchanged a look with each other, one of mutual confusion, before they shrugged, took each other's hand and went off down the hallways. Eerie silence was better than having things thrown at them and words that made Mari actually believe she was going to die that day.

* * *

When things stretched on to a month, Dia was still quite sure of her opinion. Even if they had progressed to being more comfortable around other people and with them knowing they were together. Besides, Dia had done her research and a lot of relationships, especially in early years, ended in breakups.

Which is why she still didn't say anything, or allow her expression to even twitch when Mari gave Ruby a kiss on the cheek, the poor girl burning up immediately and nearly fainting whilst Kanan raised an eyebrow at Dia.

"You're not gonna say anything about that?"

"Why should I? It's not going to last."

"Mm…" Kanan turned back to Mari and Ruby sat in the shade of the rooftop together, "I don't know, Dia. They look pretty happy."

"They look happy now, but that's only the present."

"Well… Are you going to tell me that we won't last very long by that same logic?" Kanan asked, inching her way closer.

"We're different. And I can tell you why later, but for the time being, just trust me. It won't last."

"If you say so," Kanan grinned, hugging her around the waist and lifting her off the ground briefly, "Just let them have their fun, okay?"

"Yes, of course. I'll just have to be there for Ruby when things end."

"... You're a very glass half empty person, aren't you?"

"You're only just learning that?"

* * *

It had been a full year. Whilst the third years had since left to their prospective futures, Mari would sometimes allow herself to indulge Ruby in a variety of activities, including a suspicious amount of 'private helicopter rides.' Dia didn't ask any further on that. But she still knew.

It wasn't going to last.

Now that they were apart and in different places, rather than seeing each other in school every day, now Ruby and Mari had to deal with distance. Dia didn't necessarily think things would go badly out of vindictiveness, she just couldn't quite see them as compatible. They were polar opposites in personality and it didn't settle to her that they were right.

Kanan just assumed that Dia only thought this because she simply couldn't picture Ruby with anyone else at all, because she was her pure younger sister. Dia's complacency was a little bit unsettling to her, she would've expected that anyone who would even have dared to try and date Ruby would be met with Dia's threats. Or at least an 'accident'.

But it had been a year and no 'accidents' had befallen Mari. Kanan was glad about that of course; she wasn't like Dia, she wanted this relationship to succeed. It would be odd to be friends with Mari, who had broken up with her girlfriend's sister, but that wasn't of course the only reason. Part of her just wanted Dia to stop obsessing about their relationship and about how it would end at some point in the near future, then again, that was what she had been saying since the very beginning of them dating.

At this point, they were on a double date, which Kanan was absolutely amazed that Dia had agreed to, but maybe she just wanted to spend time around the two of them to be proven right at some point and she would witness some kind of euphoria only experienced at a year's worth of suffering to only be proven right. Dia just had that kind of stoicism. Or maybe it was masochism?

That didn't matter. But Kanan couldn't help but feel out of place in a restaurant of the expensive variety and whilst Dia, Ruby and Mari came from families of an affluent nature, she came from a small diving shop. It was humble, but it was local and she lived happily enough.

The evening had gone well enough, but Dia was still as twitchy to be proven right as ever. Ruby had obviously noticed, but she was not the type to speak up on that sort of thing.

"So, how's your sex life going?"

Kanan nearly spat out her drink, but Dia seemed unfazed. It was a question expected of Mari though, but Dia answered just as honestly as ever.

"It's going fine, thank you."

"Not going to ask how ours is going?"

"I would rather not enquire about that, no."

"Mari-chan…" Ruby looked to her, whilst Mari only laughed.

"Well, here's to a year," Mari raised her glass of lemonade, "Even to those who doubted."

Mari gave Dia a knowing look, but Dia didn't appear to be fazed.

"There's still plenty of time," She returned cryptically, almost losing her facade when she watched Mari take the lemon off the rim of the glass and bite into the thin slice without flinching at the sourness. Kanan winced though.

God, she was friends with strange people. If she thought about it and listed them all off, she had a friend who literally believed she was a fallen angel (or at the very least was very convincing about acting like it), someone who marvelled about any kind of modern convenience, two sisters who was heavily opposing in just about every single way, a girl who acted demure, but with enough doujinshi crammed under her bed that you thought she had something to hide, a girl who had nearly sacrificed her life for a nice looking uniform, another who had such an unhealthy obsession with oranges she could live in a mikan tree, then an eccentric rich girl. Though, if she was being honest and sappy, Kanan would say that she wouldn't have it any other way.

"Mm, we'll see."

Kanan really didn't want to see just how long Dia would be willing to hold onto the belief that she was correct.

* * *

Mari had looked forward to this day. Another thing to shove in Dia's face that she was wrong about their relationship. Mari had heard about Dia's stance through Kanan and from that moment, she had redoubled her efforts to make her relationship with Ruby work. Not that she was intending to be lackadaisical about the whole thing. It had been many years now and Mari was wondering how long it would take Dia to give up on the ridiculous ideal that they weren't really in love and that they would just fall apart if Dia so much as snapped her fingers. But the metaphorical snap had never came.

Dia had also rented a billboard along the road in which Ruby, Mari, and just about everyone in Aqours saw quite often, with block white lettering on a black background stating, 'It won't last.' And Mari thought that she was the extravagant one.

But Mari was never one to be outdone, but upon finding that Dia still had power over the billboard for a while (the next ten years), Mari had financed an entirely new billboard to be built just past Dia's and now the fruits of her labour (money), would come to pass in the most spectacular way possible. Of course, Ruby had known about this plan and agreed to keep it a secret, even after she had accepted the engagement ring.

Mari was there to watch as well, as the men worked tirelessly to put up her message. Soon enough, the work was done and Mari was able to bask in her pure pettiness.

On this billboard, Mari had financed the message to be up for the next twenty years, just to one-up Dia further, with the same layout as the billboard prior. A black background with white lettering, but this time, a picture was present, which appeared to be a selfie of both Ruby and Mari together, the engagement ring clearly visible on Ruby's left fourth finger.

This time, the words read, 'It's going to last.'

* * *

"Dia, can't you be a little happier about this?"

"How can I be? This whole thing will just make it all the sadder when they inevitably split up."

Dia eyed Kanan in the mirror as she applied makeup, Kanan placing her hands on Dia's shoulders.

"You're the maid of honour at your sister's wedding… Don't you think it's a cause for celebration?"

Dia sighed and stood herself up abruptly from her chair, "Of course it's a celebration. But I cannot be blinded to the future."

Kanan huffed, shaking her head a little bit, "Come on Dia, don't you think it's time that you gave that up? It's been years, they're about to get married… I think they really do love each other and if they didn't, I don't think Mari would have paid for that billboard to still be up today and even past this point."

"I don't lose, Kanan, you should know that."

Kanan rubbed her neck, chuckling, although a bit nervous at the remembrance of the night before, "Yeah… I suppose I should." Kanan sighed. She always had to fight to be the dom and even then, it was only when Dia wanted her to be. Then again, she didn't really mind…

They had fallen into silence since then and before they knew it, Ruby and Mari were both stood on the altar, Dia and Kanan stood on their respective sides, as the priest read out the typically vows and so on.

"If anyone knows why this couple should not be joined in marriage, may they speak now, or forever hold their peace."

Dia and Mari made eye contact. Dia mouthed " _It's not going to last_." Whilst Mari merely grinned and Kanan shook her head. Ruby, blissfully unaware, seemed too taken by the day to notice anything.

"You may now kiss the bride."

Mari confidently took Ruby and dipped her down, passionately kissing her whilst their audience they had cheered. Dia remained silent and whilst Kanan was trying to appreciate the beauty of the situation, she just knew that this was only going to spur Dia, especially as Mari took Ruby by the hand and led her back down the aisle and out the building.

"You know what happens on a honeymoon, right?" Kanan said, moving to Dia's side.

"I've moved past that. I could storm the honeymoon suite, but that would be insensitive to the inevitable future."

Kanan let out a long sigh. She wouldn't be letting go of this anytime soon.

* * *

"Dia, I'll let you hold your niece if you admit that our relationship is going to last."

"Well," Dia shrugged, "I suppose I'm not going to hold her then."

Whilst Mari had been initially amused at Dia and her lack of a reaction about her and Ruby, yet her constant belief that they were going to break up, now it was getting rather tiresome. She knew Dia was stubborn, but she didn't know she could hold the same, frankly wrong ideal, for a relationship that had been going strong for over ten years would suddenly crumble and that she would be there to witness it.

Here Mari was, holding the swaddle of cloth that was her newborn daughter and Dia was there with her arms folded. She glanced to Kanan, who shrugged at her. She knew Kanan tried her best and she was amazed that Kanan had managed to put up with her for all this time. She supposed true love conquered all, which was ironic, all things considered.

Ruby was asleep for now on the bed, having had a tiring nine months and Mari now felt it was the appropriate time for her to confront Dia and just _try_ to get some kind of admittance out of her.

"Kanan, do you want to hold her?"

"I'd like to, yeah."

Kanan gave a slightly worried glance in Dia's direction, but she didn't seem to mind. After all, Kanan didn't have to admit anything, or claim that Dia was wrong, so Mari handed her over carefully, showing her just how to hold her without putting any unnecessary strain on the newborn's body.

Kanan smiled and used one of her fingers to gently stroke her cheek as the baby made a small gurgling noise.

"Are you sure you don't want to hold her?" Mari teased with a knowing smirk as she watched Dia's gaze on Kanan and the baby in her arms. Maybe she was breaking, finally coming to admit that -

"I'll live."

Or maybe not. Mari sighed, but otherwise preoccupied herself with watching Kanan. At least she had believed in them.

* * *

"I don't know why you're still so hung up on this…" Kanan sighed.

"Because I refuse to be wrong about this."

"It doesn't hurt to admit that you're wrong about something you said when you were seventeen. And there's no shame in it."

"... Kanan, are you wearing a wire?"

"I would not wear a wire into a maternity ward, trust me. You'd just hear screaming and crying instead of some kind of confession."

"Mm," Dia grunted, turning her attention back to her own daughter in her arms. Kanan looked to her as well, sitting herself down beside Dia's bed, "I mean, I could be wrong…" Dia said, eyes still on her daughter, who was since fast asleep, "But…"

Kanan had leant closer, but Dia suddenly shot her hand out, pulling up Kanan's shirt, revealing a wire which she pulled off, "I'm not," She said, crushing the main device in one hand, before clearing her throat and dropping it to the floor as if nothing had happened.

Kanan stood up in a bit of a daze, groaning and wondering when this whole thing would be over and Dia could just relax off this whole belief.

"Ame, it's not going to last, is it?" Dia asked, tickling the baby with one of her fingers until she cooed happily, "That's right, it's not."

"Dia _. Please_ do not make our daughter's first words be 'It's not going to last.'"

* * *

"So, how are things with you and Ruby?"

"Perfectly fine, in case you couldn't tell," Mari shifted in her seat with a small huff of effort.

Dia and Mari had been left in a room alone at this point, as if this was the ideal situation, both of them thought sarcastically. Both Ruby and Kanan were busy with their children at this point, the both of them together having some sort of play date. As well as this, Ruby was of the belief that someone needed to be spending time with Mari a lot more to ensure that things went well.

"You're not going to make a comment on how you expected us to be broken up about now?"

"Mm, there's still time," Dia shrugged, "It'll happen without my foreshadowing."

"You know, I would appreciate this conversation a lot more if I wasn't eight months pregnant with our second child."

"... Is it so that when you break up, you can both keep one of the children?"

* * *

As time went on, Dia was never correct. Even after the second child was born and years passed to allow every single one of the affectionately dubbed, 'Aqours babies' were born. Chika and Riko had stuck to only having one child, Hanamaru and Yoshiko had two little demon twins (quite literally, Yoshiko had said after being kept up every night for a week straight), whilst Kanan and Dia themselves had also had a second. Mari and Ruby did just have to go one step further than everyone else though, having had a third child, with enough wealth between both families to do more than cover the costs of raising all three.

You had taken the role of the single aunt, which she was perfectly okay with. Under the claim that she was 'married to the ocean' and that she simply didn't care for a relationship with any kind of human being. But she relentlessly doted on each and every child, even against each parent's wills. The only problem was, she had the foul mouth of a sailor and thus was sometimes sequestered from seeing any one of the children, out of fear that she would teach one of them a swear word, whether it was accidental, or, God forbid, intentionally.

Dia had since come to admit to herself that she was wrong. Or at least, being wrong for many years amounted up to a lot of doubt in her own opinion.

Not that she would ever admit that. She was still as stubborn as she was at seventeen. Besides, Mari had done well to get through Dia's constant internal criticisms, whilst also keeping Ruby as happy as possible (with the exception of both pregnancies, which resulted in a lot of crying on Ruby's part).

She hadn't even admitted to Kanan that she was wrong about their relationship, but she had since stopped being so obsessive about the whole thing. At this point, Kanan could tell that she had dropped the whole thing and she couldn't be happier.

Of course, Mari knew that Dia had given up on the whole thing. She just didn't say anything.

* * *

 **Author's note:** imagine dia as an old lady admitting to two gravestones that she was wrong. there you go, there's the angst that i always have to slip in there, courtesy of princess pana.


End file.
